1. Field of the Invention
This invention relates to vehicular lighting system, particularly to one having a housing provided with an optical reflecting surface for reflecting the light produced by LED lamps to have the light passing through an optical panel and projected out for illumination. A heat-dissipating member secured between the housing and the optical panel is installed with LED lamps and has its front end disposed with an auxiliary heat-sink that extends in a reserved space of the optical panel and combined together with the optical panel. Thus, the auxiliary heat-sink's direct contact with atmospheric temperatures enables enhanced heat dissipation effect and prolongs the service life of the LED lamps.
2. Description of the Prior Art
At present, LED lamps are employed as light sources for a car. Since the light intensity of one single LED lamp is impossible to offer enough lumen; therefore, a plurality of LED lamps have to be installed in a lamp housing for collective operation so as to produce appropriate amount of illuminance (LUX) and thus, after these LED lamps are started to emit light, high temperature will be produced and in this case, it is necessary to try to get rid of the high temperature produced by the light emitted by LED lamps and also needs to lower the temperature of the LED lamps in a shining state so as to maintain due operating temperature of the LED lamps. The optimum condition of photoelectric conversion efficiency of the LED lamps is preferably to keep the temperature of the thermal pad at 25° C. When the temperature of a packaging base plate continues to rise, the photoelectric conversion efficiency of the LED lamps will become lower. Generally, if the operating temperature of the LED lamps is around 110° C., the LED lamps can maintain about 80% of photoelectric conversion efficiency and, the higher the operating temperature is, the lower the photoelectric convention efficiency of the LED lamps will become and as a result, the LED lamps will quickly become weakened and impossible to produce enough photoelectric conversion efficiency and finally will result in trouble and damage. Therefore, a common problem confronted by using current LEDs as illuminating lamps is how to quickly dissipate high temperature of operating LED lamps, how to maintain excellent photoelectric conversion efficiency and how to prolong the service life of the LED lamps.
Therefore, for preventing LED lamps from becoming weakened quickly, the LED lamps, as disclosed in a U S patent No. 2006120094 A1, titled “Vehicular illumination lamp”, and in anther U.S. Pat. No. 8,246,225 B2, title “Head Light or fog light for motorcycles and automobiles”, are combined with a large-area heat-dissipating member for directly and quickly guide and dissipate high temperature produced by the LED lamps. However, in foresaid two U.S. patents, the heat-dissipating member is covered by an optical panel and a lamp housing (Actually, it is a common problem of conventional vehicular lighting systems using LED lamps); therefore, the heat-dissipating member can only have the heat source of the LED lamps guided to the lamp housing and then, by the lamp housing contacting with outside air of normal temperature to have high temperatures dissipated outward. Nevertheless, such a method of heat dissipation is only to have the lamp housing serving as a main heat-dissipating member so it is obvious that the structure of the conventional car lamp is insufficient in heat dissipation, especially to vehicular lighting systems that need comparatively large illumination and that is limited and contracted in volume. Therefore, the conventional LED lamps are likely to become weakened quickly and damaged due to inefficient heat dissipation.
For this reason, the inventor of this invention, having much experience in designing and manufacturing lighting systems, understands and researches the problem of heat dissipation efficiency of vehicular lighting systems and hence devised this invention.